Kconfig 5.1 KB

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  1. # SPDX-License-Identifier: GPL-2.0
  2. menu "UML-specific options"
  3. config UML
  4. bool
  5. default y
  6. select ARCH_HAS_KCOV
  7. select ARCH_NO_PREEMPT
  8. select HAVE_ARCH_AUDITSYSCALL
  9. select HAVE_ARCH_SECCOMP_FILTER
  10. select HAVE_ASM_MODVERSIONS
  11. select HAVE_UID16
  12. select HAVE_FUTEX_CMPXCHG if FUTEX
  13. select HAVE_DEBUG_KMEMLEAK
  14. select HAVE_DEBUG_BUGVERBOSE
  15. select NO_DMA
  16. select GENERIC_IRQ_SHOW
  17. select GENERIC_CPU_DEVICES
  18. select GENERIC_CLOCKEVENTS
  19. select HAVE_GCC_PLUGINS
  20. select SET_FS
  21. select TTY # Needed for line.c
  22. config MMU
  23. bool
  24. default y
  25. config NO_IOMEM
  26. def_bool y
  27. config ISA
  28. bool
  29. config SBUS
  30. bool
  31. config TRACE_IRQFLAGS_SUPPORT
  32. bool
  33. default y
  34. config LOCKDEP_SUPPORT
  35. bool
  36. default y
  37. config STACKTRACE_SUPPORT
  38. bool
  39. default y
  40. select STACKTRACE
  41. config GENERIC_CALIBRATE_DELAY
  42. bool
  43. default y
  44. config HZ
  45. int
  46. default 100
  47. config NR_CPUS
  48. int
  49. range 1 1
  50. default 1
  51. source "arch/$(HEADER_ARCH)/um/Kconfig"
  52. config MAY_HAVE_RUNTIME_DEPS
  53. bool
  54. config STATIC_LINK
  55. bool "Force a static link"
  56. depends on CC_CAN_LINK_STATIC_NO_RUNTIME_DEPS || !MAY_HAVE_RUNTIME_DEPS
  57. help
  58. This option gives you the ability to force a static link of UML.
  59. Normally, UML is linked as a shared binary. This is inconvenient for
  60. use in a chroot jail. So, if you intend to run UML inside a chroot,
  61. you probably want to say Y here.
  62. Additionally, this option enables using higher memory spaces (up to
  63. 2.75G) for UML.
  64. NOTE: This option is incompatible with some networking features which
  65. depend on features that require being dynamically loaded (like NSS).
  66. config LD_SCRIPT_STATIC
  67. bool
  68. default y
  69. depends on STATIC_LINK
  70. config LD_SCRIPT_DYN
  71. bool
  72. default y
  73. depends on !LD_SCRIPT_STATIC
  74. select MODULE_REL_CRCS if MODVERSIONS
  75. config HOSTFS
  76. tristate "Host filesystem"
  77. help
  78. While the User-Mode Linux port uses its own root file system for
  79. booting and normal file access, this module lets the UML user
  80. access files stored on the host. It does not require any
  81. network connection between the Host and UML. An example use of
  82. this might be:
  83. mount none /tmp/fromhost -t hostfs -o /tmp/umlshare
  84. where /tmp/fromhost is an empty directory inside UML and
  85. /tmp/umlshare is a directory on the host with files the UML user
  86. wishes to access.
  87. For more information, see
  88. <http://user-mode-linux.sourceforge.net/hostfs.html>.
  89. If you'd like to be able to work with files stored on the host,
  90. say Y or M here; otherwise say N.
  91. config MCONSOLE
  92. bool "Management console"
  93. depends on PROC_FS
  94. default y
  95. help
  96. The user mode linux management console is a low-level interface to
  97. the kernel, somewhat like the i386 SysRq interface. Since there is
  98. a full-blown operating system running under every user mode linux
  99. instance, there is much greater flexibility possible than with the
  100. SysRq mechanism.
  101. If you answer 'Y' to this option, to use this feature, you need the
  102. mconsole client (called uml_mconsole) which is present in CVS in
  103. 2.4.5-9um and later (path /tools/mconsole), and is also in the
  104. distribution RPM package in 2.4.6 and later.
  105. It is safe to say 'Y' here.
  106. config MAGIC_SYSRQ
  107. bool "Magic SysRq key"
  108. depends on MCONSOLE
  109. help
  110. If you say Y here, you will have some control over the system even
  111. if the system crashes for example during kernel debugging (e.g., you
  112. will be able to flush the buffer cache to disk, reboot the system
  113. immediately or dump some status information). A key for each of the
  114. possible requests is provided.
  115. This is the feature normally accomplished by pressing a key
  116. while holding SysRq (Alt+PrintScreen).
  117. On UML, this is accomplished by sending a "sysrq" command with
  118. mconsole, followed by the letter for the requested command.
  119. The keys are documented in <file:Documentation/admin-guide/sysrq.rst>. Don't say Y
  120. unless you really know what this hack does.
  121. config KERNEL_STACK_ORDER
  122. int "Kernel stack size order"
  123. default 2 if 64BIT
  124. range 2 10 if 64BIT
  125. default 1 if !64BIT
  126. help
  127. This option determines the size of UML kernel stacks. They will
  128. be 1 << order pages. The default is OK unless you're running Valgrind
  129. on UML, in which case, set this to 3.
  130. It is possible to reduce the stack to 1 for 64BIT and 0 for 32BIT on
  131. older (pre-2017) CPUs. It is not recommended on newer CPUs due to the
  132. increase in the size of the state which needs to be saved when handling
  133. signals.
  134. config MMAPPER
  135. tristate "iomem emulation driver"
  136. help
  137. This driver allows a host file to be used as emulated IO memory inside
  138. UML.
  139. config PGTABLE_LEVELS
  140. int
  141. default 3 if 3_LEVEL_PGTABLES
  142. default 2
  143. config UML_TIME_TRAVEL_SUPPORT
  144. bool
  145. prompt "Support time-travel mode (e.g. for test execution)"
  146. # inf-cpu mode is incompatible with the benchmarking
  147. depends on !RAID6_PQ_BENCHMARK
  148. depends on !SMP
  149. help
  150. Enable this option to support time travel inside the UML instance.
  151. After enabling this option, two modes are accessible at runtime
  152. (selected by the kernel command line), see the kernel's command-
  153. line help for more details.
  154. It is safe to say Y, but you probably don't need this.
  155. endmenu
  156. source "arch/um/drivers/Kconfig"